Biogen’s Phase 3 Clinical Trial for its Choroideremia Gene Therapy Doesn’t Meet Endpoints

Biogen, a global biotechnology company focused on neurological conditions, has reported that the Phase 3 STAR clinical trial for its emerging choroideremia gene therapy didn’t meet its primary endpoint of improvement in best corrected visual acuity (BCVA) of 15 letters or more at 12 months after dosing. (Fifteen letters is equivalent to three lines on an eye chart.) The company also reported that the trial didn’t meet key secondary endpoints. STAR enrolled 169 patients at sites around the world. Biogen will provide more details from the study at a future scientific meeting.

“While we had hoped for better results from Biogen’s clinical trial for its choroideremia gene therapy, we need to keep in mind that many therapies do not make it through clinical trials to receive regulatory approval. This is the nature of clinical research,” says Ben Yerxa, PhD, chief executive officer, Foundation Fighting Blindness. “That’s why we need to launch multiple therapy trials, even for the same condition, to achieve success.”

4D Molecular Therapeutics is currently conducting a Phase 1/2 clinical trial for its choroideremia gene therapy. 

Choroideremia affects approximately 1 in 50,000 people — 6,000 people in the US. As an X-linked condition, males are usually affected — females are usually unaffected carriers. Mutations in the REP-1 gene lead to degeneration of the choroid — the vasculature that provides oxygen and nourishment to the retina. Photoreceptors, the cells that make vision possible, and a layer of supportive cells known as the retinal pigment epithelium also degenerate in people with the condition.